Valve structure for controlling discharge of waste liquid into pneumatic sewage disposal system

ABSTRACT

Waste liquid is discharged into a pneumatic sewage disposal system through a discharge conduit from the outlet of a place in a kitchen or laundry or a fixture in a bathroom like a bathtub or washbasin, for example. Flow control structure is operatively associated with the discharge conduit which opens when liquid starts to flow from the outlet and closes when the flow of liquid stops.

United States Patent Inventor Sven Algot Joel Liljendahl Kallhall,Sweden Appl. No. 54,927

Filed July 15, 1970 Patented Dec. 21, 1971 Assignee AktiebolagctElectrolux Stockholm, Sweden Priority Sept. 8, 1969 Sweden 112366/69VALVE STRUCTURE FOR CONTROLLING DISCHARGE OF WASTE LIQUID INTO PNEUMATICSEWAGE DISPOSAL SYSTEM 12 Claims, 5 Drawing Figs.

Int. (:1

Field of Search E03t1l1/00, E03d 5/00, E03d 3/00 4/10, 1,41,

Primary Examiner-Henry K. Artis Attorney-Edmund A. Fenander ABSTRACT:Waste liquid is discharged into a pneumatic sewage disposal systemthrough a discharge conduit from the outlet of a place in a kitchen orlaundry or a fixture in a bathroom like a bathtub or washbasin, forexample. Flow control structure is operatively associated with thedischarge conduit which opens when liquid starts to flow from the outletand closes when the flow ofliquid stops.

CONDUIT 44 CONNECTED TO PNEUMATIC SEWAGE DISPOSAL SYSTEM AND ATA PART/ALVACUUM.

3a 43 n l I Iii 5 l. i; 25 i 76 III 1 1 i 2/ 5 l0 PRIOR ART /3 1 CONDUIT12 caxvrvecrca r0 PNEUMATIC SEWAGE DISPOSAL SYSTEM AND I A74 MET/ALvacuum. M

PATENTED M1221 Ian SHEET E OF 2 VALVE STRUCTURE FOR CONTROLLINGDISCHARGE OF WASTE LIQUID INTO PNEUMATIC SEWAGE DISPOSAL SYSTEMBACKGROUND OF THE INVENTION 1. Field of the Invention In a pneumaticsewage disposal system provision must be made for controlling thedischarge into such a sewage system of waste liquid flowing from placesin kitchens and laundries and fixtures in bathrooms like bathtubs andwashbasins, for example.

2. Description of the Prior Art FIG. 1 illustrates valve mechanism of aknown type for use in a pneumatic sewage disposal system for controllingthe discharge of waste liquid into the sewage system responsive to flowof such liquid. Waste liquid flows through a conduit 11 from a place ina kitchen or laundry or a fixture in a bathroom like a bathtub orwashbasin, for example. The waste liquid flows from the conduit 11 to avessel I and from the latter to a discharge conduit 12 which is adaptedto be connected to a pneumatic sewage disposal system and maintained ata partial vacuum or subatmospheric pressure.

The bottom of the vessel I0 is formed to provide a seat M for a valve 9which depends downward from the bottom of a float I3 which is verticallymovable within the vessel which serves as a float chamber 8. The valve 9moves toward and from its seat 14 with vertical movement of the float 13in chamber 8 responsive to rise and fall therein of waste liquid flowingthrough the conduit 11.

When the quantity of waste liquid in the float chamber 8 is sufficient,the float I3 will rise and move the valve 9 from its seat 14. When thisoccurs waste liquid will be withdrawn through discharge conduit 12 intothe pneumatic sewage system responsive to subatmospheric pressure in theconduit I2. When the liquid level in the float chamber 8 fallssufficiently the float 113 will move downward and the valve 9 in turnwill be moved downward to its closed position against the seat 14.

The valve mechanism in FIG. I functions in such manner that the valve 9will be moved to its closed position before all of the waste liquid inthe float chamber 8 has been discharged therefrom. This is objectionablebecause the waste liquid in the float chamber 8 and conduit 11 leadingthereto often develops an unpleasant odor. When grease, soap, detergentand similar materials are present in waste liquid, such materials andtheir reaction products tend to collect on the surfaces of the float I3and interior of the chamber 8. This will cause the float 113 to operatesluggishly. Further, the accumulation of objectionable material in thisway eventually can cause the float-operated valve 9 to malfunction forthe reason that the float I3 cannot move freely in its chamber.

SUMMARY OF THE INVENTION My invention relates to controlling thedischarge of waste liquid from places in kitchens and laundries andfixtures in bathrooms like bathtubs and washbasins, for example, into apneumatic sewage disposal system by improved valve structure which opensautomatically when flow of waste liquid starts and automatically closesonly when the flow of waste liquid stops and all of the liquid has beendischarged into the sewage disposal system.

l accomplish this by providing in a discharge conduit, which is adaptedto be maintained at a partial vacuum and through which waste liquid fromthe outlet of such a place is discharged into a pneumatic sewagedisposal system, a main valve and operating manes therefor which opensthe main valve responsive to a partial vacuum and closes the main valveresponsive to atmospheric pressure.

The discharge conduit includes a vessel defining a float chamber inwhich a float is movable up and down with rise and fall of liquidtherein. The main valve operating means is connected to a region of thedischarge conduit downstream from the main valve by a control valve whenit is moved to one of its two operating positions responsive to upwardmovement of the float. The main valve operating means is connected tothe float chamber by the control valve when it is moved to the other ofits two positions responsive to downward movement of the float.

An important feature of my invention is that, when flow of waste liquidstarts in the discharge conduit, the float-operated control valve isactivated by a small quantity of waste liquid flowing into the floatchamber and is moved to the one of its two operating positions. When thecontrol valve is activated in this manner, the main valve operatingmeans is connected to the discharge conduit and the main valve operatingmeans become operable to open the main valve responsive to the partialvacuum prevailing in the discharge conduit.

When this occurs the liquid in the float chamber is sucked out veryquickly and the float moves down to its lowest position, thereby causingthe control valve to move to the other of its two positions. Since themain .valve previously has been opened, the float chamber will be incommunication with that part of the discharge conduit in which a partialvacuum is adapted to be maintained, so that a partial vacuum also willprevail in the float chamber. The partial vacuum prevailing in the floatchamber will be transmitted to the main valve operating means when thecontrol valve moves to the other of its two positions responsive tomovement of the float to its lowest position in the float chamber.

Although the partial vacuum prevailing in the float chamber is less thanthe partial vacuum in the discharge conduit which is relied upon tocause the main valve operating means to open the main valve,nevertheless it is sufficient to render the main valve operating meansoperable to keep the main valve open while waste liquid flows from theoutlet to the float chamber. The passageway in which waste liquid flowsfrom the outlet to the float chamber is so constructed and formed thatthe waste liquid will function to block flow of ambient air atatmospheric pressure from the outlet to the float chamber, so that thelatter will be maintained at a partial vacuum.

When the flow of waste liquid from the outlet to the float chamberstops, ambient air at atmospheric pressure flows into the float chamber,and, by reason of the fact that the float chamber is connected to themain valv-e operating means, the latter will be rendered operable toclose the main valve after practically all of the waste liquid has beendischarged into the pneumatic sewage disposal system.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, FIG. I, is a verticalsectional view more or less diagrammatically illustrating valvemechanism of a known type intended for use in a pneumatic sewagedisposal system for controlling the discharge of waste liquid into thesewage system responsive to flow of such waste liquid;

FIG. 2 is an elevation view, partly in section, of valve structure whichembodies the invention for controlling the discharge of waste liquidinto a pneumatic sewage disposal system responsive to flow of such wasteliquid;

FIG. 3 is an enlarged fragmentary sectional view of the float-operatedvalve mechanism shown in FIG. 2',

FIG. 4 is an enlarged perspective view, partly in section, of thepneumatically-operated valve mechanism shown in FIG. 2 which coacts withthe float-operated valve mechanism; and

FIG. 5 is an enlarged fragmentary sectional view of parts shown in FIG.4 to illustrate details more clearly.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 2 l have shown myinvention embodied in a pneumatic sewage disposal system for controllingthe discharge of waste liquid into the sewage system responsive to flowof such liquid. Waste liquid flows through a conduit 20 from the outlet42 of a place 43 in a kitchen or laundry or a fixture in a bathroom likea bathtub or washbasin, "for example. The waste liquid flows from theconduit 20 into a discharge conduit 23 which is in communication with aconduit 44 adapted to be connected to a pneumatic sewage disposal systemand maintained at a partial vacuum which may be one-half of atmosphericpressure, for example.

Flow control structure is operatively associated with the dischargeconduit 23 which opens when liquid starts to flow from the outlet 42 andcloses when such flow of liquid stops. The flow control structureincludes a main valve 24 coupled in the discharge conduit 23 at a regiondownstream from and in communication with the outlet 42. As seen in FIG.4, the valve 24 is embodied in a section of the discharge conduit 23having an oval-shaped opening in the top thereof and an inverted U-shaped bottom 45 at the region of such top opening. A ridge 46, which istransverse to the longitudinal axis of the conduit 23, extends inwardtherefrom about the conduit between the opposing edges of the topopening.

An elastic wall 47 of the shape shown in FIG. 4 is positioned at the topopening of the conduit 23. The elastic wall, which may be formed ofrubber, for example, is provided with a flange 48 which fits in anairtight manner over an outwardly bent edge 49 about the top opening inthe conduit 23. The elastic wall 47 serves as a valve member of thevalve 24 and is movable between closed and open positions to control thedischarge of waste liquid from the discharge conduit 23 into the conduit44 forming a part of the pneumatic sewage disposal system.

A device is provided to operate the main valve 24 and move the elasticvalve member 47 between its closed and open positions. In FIG. 4 it willbe seen that the elastic valve member 47 is formed with bosses 50 and 51in which lifting buttons 52 and 53 are vulcanized. The buttons 52 and 53coact with pairs of spaced horizontal bars 54 and 55 which are fixed toand project from two arms 56 and 57 of the operating device 25. The arms56 and 57 have bottom edges of semicircular form which, along theirentire lengths, can engage the elastic valve member 47 and press thelatter into sealing engagement with the bottom 45 of the conduit 23 atopposing sides of the ridge 46, as shown in FIG. 5.

The arms 56 and 57 are formed at the periphery of a plate 58 whichdepends downward from and is fixed to the bottom 59 of an uprightcylindrical-shaped vessel 60 having a sidewall 61 and in which a metalweight 62 is positioned. Another inverted U-shaped vessel 63 is disposedabove and spaced from the vessel 60.

The vessel 63 is supported in a fixed position in any suitable manner,as by a frame 64, for example, and includes a top 65 and a sidewall 66extending downward therefrom. The bottom edge of the sidewall 66 ofvessel 63 and top edge of the sidewall 61 of the vessel 60 are connectedby a member 67 of annular shape which is formed of a suitable resilientmaterial like rubber, for example. The annular-shaped member 67 issecured to the sidewall 61 and 66 in an airtight manner.

When the operating device 25 is connected to a region at a partialvacuum in a manner that will be explained presently, the vessel 60 willmove upward with respect to vessel 63 due to the resilient connection 67therebetween. When this occurs the plate 58 and arms 56 and 57 will bemoved upward and lift the buttons 52 and 53, thereby lifting the elasticvalve member 47 from its closed or seated position in the conduit 23.

Conversely, when the operating device 25 is connected to a region at ahigher pressure, such as atmospheric pressure, in a manner that will beexplained presently, the vessel 60, with the aid of the weight 62, willmove downward with respect to the vessel 63 due to the resilientconnection between the vessels. When this occurs the plate 58 will bemoved downward and the arms 56 and 57 will exert force against theelastic valve member 47 and move it firmly against the bottom 45 of theconduit 23 at opposing sides of the ridge 46.

The main valve 24 and operating device 25 just described are generallylike those described in my U.S. Pat. No. 3,482,267, granted Dec. 9,I969. The disclosure in my aforementioned patent may be considered asbeing incorporated in this application, and, if desired, reference maybe made thereto for a detailed description of the main valve 24 andoperating device 25 The operating device 25 is connected by a conduitsection 29, a control valve 28 and a conduit 27 to a region 26 of thedischarge conduit 23 which is at a partial vacuum and downstream fromthe main valve 24. In a manner that will be described presently, theoperating device 25 is connected by conduit section 29 and passagewaymeans formed in the control valve 28 to a chamber 71 and will beinfluenced by the pressure prevailing in the latter which may be at apartial vacuum or at atmospheric pressure.

As seen in FIG. 3 the control valve 28 comprises a hollow body 31 havinga chamber 68 communicating with a passageway 69. The conduit section 29is connected by a nipple 33 to the chamber 68 and the conduit section 27is connected by a nipple 32 to the passageway 69. A valve member 70comprising a cylindrical-shaped part 35 having a resilient sleeve orbushing 36 thereon is axially movable within the chamber 68. A wall ofthe chamber 68 serves as a seat 34 against which the bushing 36 bearswhen the valve 28 is in its illustrated closed position which may bereferred to as the other of the two operating positions of the valve 28.

The valve member 70 is movable toward the right in FIG. 3 to its openposition which may be referred to as one" of the two operating positionsof the valve 28. In such open position the bushing 36 is moved from itsseat 34 and the conduit sections 29 and 27 are in communication with oneanother through the chamber 68 and passageway 69 in the hollow body 31.As seen in FIG. 3, the cylindrical-shaped member 35 is formed with anaxially extending groove 42 at its periphery which provides a passagewayfrom the chamber 68 within the hollow body 31 into the chamber 71 inwhich the control valve 28 is disposed.

In view of the foregoing, it will now be understood that when the valvemember 70 of the control valve 28 is open and in one of its twooperating positions with the bushing 36 moved from its seat 34, theconduit sections 27 and 29 and connection therebetween, which is formedby the chamber 68 and passageway 69 in the valve body 31, constitutemeans for connecting the operating device 25 of the main valve 24 to theregion 26 of the discharge conduit 23 which is at a partial vacuum. Whenthis occurs the elastic valve member 47 of the main valve 24 moves toits open position, as previously explained.

When the valve member 70 of the control valve 28 is closed and in theother" of its two operating positions, the operating device 25 of themain valve 24 is disconnected from the region 26 of the dischargeconduit 23. Under these conditions the operating device 25 of the mainvalve 24 is connected to the chamber 71 and influenced by the pressureprevailing therein which may be partial vacuum or atmospheric pressure,as will be explained hereinafter. This connection includes the conduitsection 29, chamber 68 of the valve body 31 and the groove 42 in thecylindrical-shaped member 35.

In accordance with my invention I provide sensing means in the dischargeconduit 23 between the outlet 42 and the main valve 24 which functionswhen waste liquid starts to flow from the outlet 42 to move the controlvalve 28 to its open position or one" of its two operating positions andrender the operating device 25 operable to open the main valve.

In my preferred embodiment the discharge conduit 23 includes a vessel 15between the main valve 24 and the outlet 42 which defines the chamber 71and the sensing means comprises a float 16 in the chamber 71 which isoperatively connected by mechanism 72 to the control valve 28. The

lower end pivotally connected to the top of the float 16 in any suitablemanner (not shown). The upper end of the link 37 is pivotally connectedto a horizontally extending arm of an L- shaped lever 30 at a regionintermediate its ends. The lever 30 at the bend thereof is provided witha pin 40 which is journaled in an opening of a stationary plate 41mounted on the hollow body 31 of the control valve 28.

The outer end of the cylindrical-shaped part 35 of the valve member 70is formed with a recess 38 which receives the upper end 39 of thevertically disposed arm of the L-shaped lever 30. The mechanism 72 justdescribed functions in such manner that the part 35 moves to the left inMG. 3 toward the closed position or the "other" operating position ofthe valve 23 responsive to downward movement of the float to.Conversely, the part 35 moves to the right in lFlG. 3 to the openposition or the one" operating position of the valve 28: responsive toupward movement of the float 116.

As seen in lFlG. 2, the control valve 2% is disposed within the vesselwhich has a removable top 17 and an overlying sealing cover lllitherefor which is formed of rubber, for example. The top 117 and sealingcover llll are formed with aligned openings to provide a vent W for thechamber 7ll.

A dislt 2ll is provided at the region waste liquid flows from theconduit 20 into the float chamber 71. The dislr 211, which is formedwith an opening 22, serves as a flow-reducing member past which wasteliquid flows from the outlet 42 to the fioat chamber 71. The opening 22in the disk 21 preferably is of such size that the quantity of liquidflowing from the outlet 32 to the chamber 71 in a given interval of timenever exceeds the quantity of liquid sucked and withdrawn from thechamber 7 i in the same given interval of time and discharged into thesewage disposal system by the partial vacuum prevailing in the dischargeconduit 23.

When the main valve 24 and control valve 28 are both closed, the floatllh will be in its lowest position in the chamber 711. Under theseconditions the body of air in the chamber 711 will be at atmosphericpressure by reason of the vent i9 provided at the top of the vessel 15and the fact that ambient air at atmospheric pressure can pass into thebottom of chamber 7ll through the conduit 20 from the place 43. Sincethe valve member 70 is closed, a passageway for air at atmosphericpressure is established from the chamber 711 to the operating device 25which includes the groove d2 in the cylindricalshaped part 35, chamber68 in the valve body iii and conduit section 29. For this reason themain valve 2 1 is closed in the manner previously explained.

When the main valve 24 is closed a partial vacuum prevails at region 26of the discharge conduit 23 which is downstream from the main valve 24.With the valve member 70 of control valve 28 in its closed position,conduit section 27 will not be in communication with the conduit section29 and a partial vacuum will prevail only in the conduit section 27.

Let us now assume that waste liquid starts to flow from the outlet 42 ofthe place 42 through the conduit 20 into thetfloat chamber 7i. In ashort interval of time with a relatively little rise in liquid level inthe chamber 711, the liquid level will rise sufficiently to lift thefloat l6 and render the latter operable to effect opening of the controlvalve 28. Air in the chamber 711 will be vented therefrom through thevent 19 with upward movement of the float 116. This will cause the valvemember 70 to move to the right in H6. 3 and connect conduit sections 27and 29. When this occurs the operating device 25 will be connected tothe region 26 at a partial vacuum through the conduit section 27,passageway 69 and chamber 68 in the valve body and the conduit section29, whereby the main valve 2d will open in the manner previouslyexplained.

When the main valve 2d opens the partial vacuum prevailing in thedischarge conduit 23 immediately becomes effective to suck and withdrawwaste liquid from the chamber 711, thereby effecting movement of thefloat in to its lowest position and closing the control valve 28. Bydimensioning the opening 22 in the disk 211 to effect flow control ofwaste liquid in the manner explained above, the liquid flowing into thefloat chamber 7i will be continuously sucked out through the dischargeconduit 23 and only an insignificant quantity of waste liquid willremain in the bottom of the float chamber 71. Hence, the float 16 willremain in its lowest position and control valve 2% will be closed duringthe entire time that waste liquid is being withdrawn from the floatchamber 7ll by the partial vacuum in the conduit 23.

The apertured flow-reducing member 2ll also functions to prevent thepressure in the float chamber ill from materially increasing andbecoming equalized with the atmospheric pressure of amhient airenveloping the vessel during removal of waste liquid from the chamber71. Stated another way, the apertured dish 21 is so constructed andformed that waste liquid flowing from the outlet $2 to the float chamber71 will blDCl-t the flow of ambient air at atmospheric pressuretherethrough sufficiently so that the partial vacuum prevailing in theconduit 2d will also mainly prevail in the float chamber 7ll. Thisoperating condition is established even though the float chamber 711 hasthe vent 119 which provides a restricted passageway for ambient air atatmospheric pressure into the float chamber.

Hence, even after the float 116 falls to its lowest level in the chamber7i and the valve member 70 of the control valve 2% moves against itsseat to disconnect conduit section 29 from conduit section 27, thepartial vacuum prevailing in the chamber 711 will function to render theoperating means 25 operable to keep main valve 24 open. Under theseconditions the partial vacuum in the chamber 71 will be transmitted tothe main valve operating means 25 through a connection formed by thegroove 32 in the cylindrical-shaped part 35, chamber titi in the valvebody 31 and the conduit section 29. Hence, the main valve 24 will remainopen during the entire time that waste liquid from the outlet 42 isbeing sucked through the discharge conduit 23 into the sewage disposalsystem. And, in view of the explanation just given, waste liquid willcontinue to be sucked out through discharge conduit 23 while the mainvalve 243 is open and the control valve 2% is closed due to the float l6being in its lowest position in the chamber 7ll.

The main valve 2d will close only after all of the waste liquid has beensucked out of the chamber 711. When all of the waste liquid has beendischarged from the place 43 and the conduit 2% is empty, ambient air atatmospheric pressure can then pass from the place 43 through conduit 201into the chamber 711. Under these conditions the ambient air enteringthe chamber 711 will increase the pressure therein to such an extentthat the partial vacuum in the chamber and transmitted through conduitsection 29 to the device 25 will be insufficient for the latter to keepthe main valve 2d open. When the main valve 24 now is closed there willbe practically no waste liquid remaining in the conduit 2(1 and thefloat chamber 7ll.

When both the main valve 24 and] control valve 28 are closed and thecontrol valve 28 opens with upward movement of the float lib responsiveto waste liquid flowing into the float chamber 711, the partial vacuumtransmitted from the region 26 of the discharge conduit 23 to theoperating device 25 is of suflicient magnitude to lift the elastic valve47 from its closed to its open position. After the elastic valve d7 isin its open position, the partial vacuum necessary to keep it open isconsiderably less than that required to move it to its open position.Hence, after the control valve 28 closes with movement of the float 116to its lowest position, the main valve 241 will remain open to suclr outall of the waste liquid from the float chamber 711 in the mannerexplained above because the partial vacuum that is maintained in thefloat chamber, although it is less than the partial vacuum prevailing inthe region 26 of the discharge conduit 23 when the elastic valve 17 ismoved to its open position, is nevertheless sufticient and adequate tokeep the elastic valve 47 open until all of the waste liquid has beendischarged from the chamber 711 and conduit 20. When this occurs ambientair at atmospheric pressure can then pass from the place 43 throughconduit 20 into the float chamber 7i, as just explained, whereby thepressure in the float chamber will increase and cause the operatingdevice 25 to close the main valve 2d.

lclaim:

ii. The combination with a pneumatic sewage disposal system, of

a. a discharge conduit which is adapted to be maintained at a partialvacuum and through which waste liquid is discharged into the sewagedisposal system from a place having an outlet,

valve is disposed in said float chamber.

system, of

b. flow control structure operatively associated with said dischargeconduit which opens when liquid starts flowing from the outlet andcloses when such flow of liquid stops,

. said flow control structurecomprising a main valve coupled in saiddischarge conduit at a region thereof downstream from and incommunication with the outlet,

d. operating means for opening said main valve responsive to a partialvacuum and for closing said main valve responsive to atmosphericpressure,

e. said discharge conduit including a vessel which is disposed betweensaid main valve and the outlet, said vessel defining a float chamber,

a float movable up and down in said float chamber responsive to rise andfall, respectively, of liquid therein,

g. a control valve having two operating positions,

h. means including said control valve in one of its operating positionsfor connecting said main valve operating means to a region of saiddischarge conduit downstream from said main valve,

. means including said control valve in the other of its operatingpositions for connecting said main valve operating means to said floatchamber,

j. means for moving said control valve to its one and other operatingpositions responsive to up and down movement, respectively, of saidfloat, and

k. said flow control structure being so constructed and formed that saidfloat chamber is maintained at a partial vacuum when waste liquid flowsfrom the outlet and at atmospheric pressure when the flow of wasteliquid from the outlet stops.

2. Apparatus as set forth in claim 1 in which said flow controlstructure is so constructed and formed that waste liquid flowing fromthe outlet to said float chamber functions to block flow of ambient airat atmospheric pressure from the outlet to said float chamber.

3. Apparatus as set forth in claim 1 which includes an aper- 4.Apparatus as set forth in claim 1 in which said control 5. Apparatus asset forth in claim 1 in which said vessel is provided with an opening inthe upper part thereof which serves as a vent for said float chamber.

6. The combination with a pneumatic sewage disposal a. a dischargeconduit which is adapted to be maintained at a partial vacuum andthrough which waste liquid is discharged into the sewage disposal systemfrom a place having an outlet,

b. flow control structure operatively associated with said dischargeconduit which opens when liquid starts flowing from the outlet andcloses when such flow of liquid stops,

c. said flow control structure comprising a main valve coupled in saiddischarge conduit at a region thereof downstream from and incommunication with the outlet,

d. operating means for opening said main valve responsive to a partialvacuum and for closing said main valve responsive to atmosphericpressure,

c. said discharge conduit including a vessel which is disposed betweensaid main valve and the outlet, said vessel defining a float chamber,

f. a float movable up and down in said float chamber responsive to riseand fall, respectively, of liquid therein,

g. means connecting said main valve operating means to a region of saiddischarge conduit downstream from said main valve, said last-mentionedmeans including a first conduit section connected to said last-mentionedregion and a second conduit section connected to said main valveoperating means and a control valve interposed therebetween,

h. said control valve having a valve member movable between open andclosed positions for respectively opening and closing the connectionbetween said first and second conduit sections,

. said control valve having passageway means which, when said valvemember is in its closed position, is in communication with said firstconduit section,

j. means including said first conduit section and said passageway meansfor connecting said main valve operating means to said float chamberwhen said valve member is in its closed position,

k. means for moving said valve member to its open and closed positionsresponsive to up and down movement, respectively, of said float, and

1. said flow control structure being so constructed and formed that saidfloat chamber is at a partial vacuum when waste liquid flows from theoutlet and at atmospheric pressure when the flow of waste liquid fromthe outlet stops.

7. Apparatus as set forth in claim 6 in which said flow controlstructure is so constructed and formed that waste liquid flowing fromthe outlet to said float chamber functions to block flow of ambient airat atmospheric pressure from the outlet to said float chamber.

8. Apparatus as set forth in claim 6 in which said control valve is soconstructed and formed that said passageway means is in communicationwith both said first and second conduit sections when said valve memberis in its open position.

9. Apparatus as set forth in claim 6 which includes an apertured memberpast which liquid flows from the outlet of the place to said floatchamber, said apertured member being so constructed and formed that therate at which liquid flows in a given interval of time from the outletto said float chamber will never exceed the rate at which liquid iswithdrawn from said float chamber in said given interval of timeresponsive to partial vacuum in said discharge conduit.

10. Apparatus as set forth in claim 6 in which said control valve isdisposed in said float chamber.

11. Apparatus as set forth in claim 6 in which said vessel is providedwith an opening in the upper part thereof which serves as a vent forsaid float chamber.

12. Apparatus as set forth in claim 6 in which said valve member of saidcontrol valve comprises a cylindrical-shaped part, said part having agroove defining said passageway means.

1. The combination with a pneumatic sewage disposal system, of a. adischarge conduit which is adapted to be maintained at a partial vacuumand through which waste liquid is discharged into the sewage disposalsystem from a place having an outlet, b. flow control structureoperatively associated with said discharge conduit which opens whenliquid starts flowing from the outlet and closes when such flow ofliquid stops, c. said flow control structure comprising a main valvecoupled in said discharge conduit at a region thereof downstream fromand in communication with the outlet, d. operating means for openingsaid main valve responsive to a partial vacuum and for closing said mainvalve responsive to atmospheric pressure, e. said discharge conduitincluding a vessel which is disposed between said main valve and theoutlet, said vessel defining a float chamber, f. a float movable up anddown in said float chamber responsive to rise and fall, respectively, ofliquid therein, g. a control valve having two operating positions, h.means including said control valve in one of its operating positions forconnecting said main valve operating means to a region of said dischargeconduit downstream from said main valve, i. means including said controlvalve in the other of its operating positions for connecting said mainvalve operating means to said float chamber, j. means for moving saidcontrol valve to its one and other operating positions responsive to upand down movement, respectively, of said float, and k. said flow controlstructure being so constructed and formed that said float chamber ismaintained at a partial vacuum when waste liquid flows from the outletand at atmospheric pressure when the flow of waste liquid from theoutlet stops.
 2. Apparatus as set forth in claim 1 in which said flowcontrol structure is so constructed and formed that waste liquid flowingfrom the outlet to said float chamber functions to block flow of ambientair at atmospheric pressure from the outlet to said float chamber. 3.Apparatus as set forth in claim 1 which includes an apertured memberpast which liquid flows from the outlet of the place to said floatchamber, said apertured member being so constructed and formed that therate at which liquid flows in a given interval of time from the outletto said float chamber will never exceed the rate at which liquid iswithdrawn from said float chamber in said given interval of timeresponsive to partial vacuum in said discharge conduit.
 4. Apparatus asset forth in claim 1 in which said control valve is disposed in saidfloat chamber.
 5. Apparatus as set forth in claim 1 in which said vesselis provided with an opening in the upper part thereof which serves as avent for said float chamber.
 6. The combination with a pneumatic sewagedisposal system, of a. a discharge conduit which is adapted to bemaintained at a partial vacuum and through which waste liquid isdischarged into the sewage disposal system from a place having anoutlet, b. flow control structure operatively associated with saiddischarge conduit which opens when liquid starts flowing from the outletand closes when such flow of liquid stops, c. said flow controlstructure comprising a main valve coupled in said discharge conduit at aregion thereof downstream from and in communication with the outlet, d.operating means for opening said main valve responsive to a partialvacuum and for closing said main valve responsive to atmosphericpressure, e. said discharge conduit including a vessel which is disposedbetween said main valve and the outlet, said vessel defining a floatchamber, f. a float movable up and down in said float chamber responsiveto rise and fall, respectively, of liquid therein, g. means connectingsaid main valve operating means to a region of said discharge conduitdownstream from said main valve, said last-mentioned means including afirst conduit section connected to said last-mentioned region and asecond conduit section connected to said main valve operating means anda control valve interposed therebetween, h. said control valve having avalve member movable between open and closed positions for respectivelyopening and closing the connection between said first and second conduitsections, i. said control valve having passageway means which, when saidvalve member is in its closed position, is in communication with saidfirst conduit section, j. means including said first conduit section andsaid passageway means for connecting said main valve operating means tosaid float chamber when said valve member is in its closed position, k.means for moving said valve member to its open and closed positionsresponsive to up and down movement, respectively, of said float, and l.said flow control structure being so constructed and formed that saidfloat chamber is at a partial vacuum when waste liquid flows from theoutlet and at atmospheric pressure when the flow of waste liquid fromthe outlet stops.
 7. Apparatus as set forth in claim 6 in which saidflow control structure is so constructed and formed that waste liquidflowing from the outlet to said float chamber functions to block flow ofambient air at atmospheric pressure from the outlet to said floatchamber.
 8. Apparatus as set forth in claim 6 in which said controlvalve is so constructed and formed that said passageway means is incommunication with both said first and second conduit sections when saidvalve member is in its open position.
 9. Apparatus as set forth in claim6 which includes an apertured member past which liquid flows from theoutlet of the place to said float chamber, said apertured member beingso constructed and formed that the rate at which liquid flows in a giveninterval of time from the outlet to said float chamber will never exceedthe rate at which liquid is withdrawn from said float chamber in saidgiven interval of time responsive to partial vacuum in said dischargeconduit.
 10. Apparatus as set forth in claim 6 in which said controlvalve is disposed in said float chamber.
 11. Apparatus as set forth inclaim 6 in which said vessel is provided witH an opening in the upperpart thereof which serves as a vent for said float chamber. 12.Apparatus as set forth in claim 6 in which said valve member of saidcontrol valve comprises a cylindrical-shaped part, said part having agroove defining said passageway means.